946 research outputs found
Single nucleotide polymorphisms (SNPs) in genes related to innate immune response against Salmonella in nursery pigs
The objective of this study was to investigate the association of single nucleotide polymorphisms (SNPs) in innate immune response genes with Salmonella shedding in nursery pigs. One hundred and sixty eight pigs on seven farrow-to- finish farms and one farrow-feeder operation were included in the study. On each farm, 21 pigs were selected from seven sows at weaning. Fecal samples were collected from selected pigs and cultured for Salmonella, and the isolates were serotyped. DNA was extracted from liver samples and used to genotype pigs for single nucleotide polymorphisms (SNPs) in 21 different innate immune response genes. In total, 15 (9.3%) pigs tested positive for Salmonella; the isolates from six pigs from four different litters on one farm were serotyped as Salmonella Infantis and from nine pigs from six different litters on another farm as Salmonella Worthington. SNP analysis showed an association of Salmonella shedding with a SNP in the genes encoding mannan-binding lectin (MBL)-associated serine protease-2 (MASP-2) and Toll-like receptor-1 (TLR-1) (P \u3c 0.05). These findings suggest that Salmonella shedding in pigs is controlled by genetic elements and these genetic variants could possibly be used to breed pigs that are more resistant to Salmonella colonization and Salmonella shedding
Charged Lepton Flavor Physics and Extra Dimensions
We estimate the charged lepton electric dipole moments and the branching
ratios of radiative lepton flavor violating decays in the framework of the two
Higgs doublet model with the inclusion two extra dimensions. Here, we consider
that the new Higgs doublet is accessible to one of the extra dimensions with a
Gaussian profile and the fermions are accessible to the other extra dimension
with uniform zero mode profile. We observe that the numerical values of the
physical quantities studied enhance with the additional effects due to the
extra dimensions and they are sensitive to the new Higgs localization.Comment: 23 pages, 13 page
Top Compositeness at the Tevatron and LHC
We explore the possibility that the right-handed top quark is composite. We
examine the consequences that compositeness would have on
production at the Tevatron, and derive a weak constraint on the scale of
compositeness of order a few hundred GeV from the inclusive cross
section. More detailed studies of differential properties of
production could potentially improve this limit. We find that a composite top
can result in an enhancement of the production rate at
the LHC (of as much as compared to the Standatd Model four top rate). We
explore observables which allow us to extract the four top rate from the
backgrounds, and show that the LHC can either discover or constrain top
compositeness for wide ranges of parameter space.Comment: 9 pages, 4 figure
Spatial mapping of band bending in semiconductor devices using in-situ quantum sensors
Band bending is a central concept in solid-state physics that arises from
local variations in charge distribution especially near semiconductor
interfaces and surfaces. Its precision measurement is vital in a variety of
contexts from the optimisation of field effect transistors to the engineering
of qubit devices with enhanced stability and coherence. Existing methods are
surface sensitive and are unable to probe band bending at depth from surface or
bulk charges related to crystal defects. Here we propose an in-situ method for
probing band bending in a semiconductor device by imaging an array of
atomic-sized quantum sensing defects to report on the local electric field. We
implement the concept using the nitrogen-vacancy centre in diamond, and map the
electric field at different depths under various surface terminations. We then
fabricate a two-terminal device based on the conductive two-dimensional hole
gas formed at a hydrogen-terminated diamond surface, and observe an unexpected
spatial modulation of the electric field attributed to a complex interplay
between charge injection and photo-ionisation effects. Our method opens the way
to three-dimensional mapping of band bending in diamond and other
semiconductors hosting suitable quantum sensors, combined with simultaneous
imaging of charge transport in complex operating devices.Comment: This is a pre-print of an article published in Nature Electronics.
The final authenticated version is available online at
https://dx.doi.org/10.1038/s41928-018-0130-
The Maritime Labour Convention, 2006 – Reflections on Challenges for Flag State Implementation
This paper begins by providing a brief overview of the International Labour Organization’s Maritime Labour Convention, 2006 (MLC, 2006), noting that this Convention, often called the “Seafarers’ bill of rights”, seeks to achieve both social and labour rights (“decent work”) for seafarers and fair competition (achieving a level-playing field) for shipowners. It has been described as the “fourth pillar” of the international maritime regulatory regime complementing the major International Maritime Organization conventions. The paper provides a brief update on international efforts to achieve the 30/33 formula needed to bring the Convention into force [at present, the tonnage element, 33% has been achieved already with coverage now at 54% of the world fleet (by gross tonnage), with 18 ratifications]. It then explores challenges faced by flag States in connection with capacity to implement the ship inspection and certification system under the MLC, 2006 and other difficulties with respect to legal implementation by the flag States. The paper also comments on some challenges in connection with port State, coastal State and labour-supplying State responsibilities. The paper points out that the MLC, 2006 is a comprehensive code that covers diverse issues and a wider range of both ships and seafarers than previous conventions. It often requires interdepartmental cooperation to implement its requirements at the national level. The paper concludes that, despite the slower pace of ratification in some regions, largely because of the recent economic and other crises, it appears that many actors in the maritime sector are already actively engaged in MLC, 2006 implementation, often ahead of governments. The question is not “if” but “when” the formula will be achieved to allow the MLC, 2006 to enter into force
New Higgs Production Mechanism in Composite Higgs Models
Composite Higgs models are only now starting to be probed at the Large Hadron
Collider by Higgs searches. We point out that new resonances, abundant in these
models, can mediate new production mechanisms for the composite Higgs. The new
channels involve the exchange of a massive color octet and single production of
new fermion resonances with subsequent decays into the Higgs and a Standard
Model quark. The sizable cross section and very distinctive kinematics allow
for a very clean extraction of the signal over the background with high
statistical significance. Heavy gluon masses up to 2.8 TeV can be probed with
data collected during 2012 and up to 5 TeV after the energy upgrade to
TeV.Comment: 27 pages, 22 figures. V2: typos corrected, matches published versio
Manifestations of Top Compositeness at Colliders
We explore the possibility that the right-handed top quark is composite,
identifying possible signatures of compositeness and how they might manifest
themselves at the LHC and Tevatron. We perform a complete analysis of the
dimension six modifications of the top coupling to gluons and find that
cancellations among operators in the t\bar{t} rate allow for very low
compositeness scales, but this can be drastically improved by looking at
kinematic distributions. Turning to the LHC, we examine four top production
from a dimension six four-top operator and estimate the LHC with 100 {\rm
fb}^{-1} collected luminosity to be sensitive to compositeness scales as high
as 5 TeV.Comment: 8 pages, 6 figures, updated figure 6, updated references, final
version published in JHE
Search for anomalous top-gluon couplings at LHC revisited
Through top-quark pair productions at LHC, we study possible effects of
nonstandard top-gluon couplings yielded by SU(3)xSU(2)xU(1) invariant
dimension-6 effective operators. We calculate the total cross section and also
some distributions for p p -> t tbar X as functions of two anomalous-coupling
parameters, i.e., the chromoelectric and chromomagnetic moments of the top,
which are constrained by the total cross section sigma(p pbar -> t tbar X)
measured at Tevatron. We find that LHC might give us some chances to observe
sizable effects induced by those new couplings.Comment: One comment and related two refs. added. Final version (to appear in
Eur.Phys.J. C
Theories for the Fermi Scale
I give a short review of our present understanding of new theories of the
electroweak scale, with emphasis on recent progress. Plenary talk at the EPS
2007 Conference at Manchester.Comment: 14 pages, EPS 2007 Conferenc
The effects of non-universal extra dimensions on the radiative lepton flavor decays \mu\to e\gamma and \tau\to \mu\gamma in the two Higgs doublet model
We study the effect of non-universal extra dimensions on the branching ratios
of the lepton flavor violating processes \mu\to e\gamma and \tau\to \mu\gamma
in the general two Higgs doublet model. We observe that these effects are small
for a single extra dimension, however, in the case of two extra dimensions
there is a considerable enhancement in the additional contributions.Comment: 16 Pages, 9 Figure
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